Silent installation with CHECKFORUPDATESATSTARTUP=0 does not disable the automatic update notification when ArcGIS Pro is already installed on the machine.
This issue could not be reproduced. Installing to set the key at 0, all subsequent installations over the already installed ArcGIS Pro maintains the reg key to 0. It was provided =0, omitted that property and given a value of 1 and all resulted in the registry value remaining at 0.
解决办法
Uninstall ArcGIS Pro before running the silent install:
Whether or not ArcGIS Pro has been installed on the machine prior, removing the existing ArcGIS Pro installation ensures that the CHECKFORUPDATESATSTARTUP=0 parameter is properly applied during a silent install.
The Windows Registry can be modified post-silent installation to 'fix' the defective behavior: